In the Madhab of Imam Abu Haneefa (RA) even the Taubah of an apostate is accepted.
Creation of Bangladesh had colossal impact on Muslims in Pakistan, India and Bangladesh itself. Citizens of Bangladesh should realise that and the sooner they come to that realisation the better it would be for everyone.
Pakistan should offer an unreserved apology to Bangladesh for perceived and actual atrocities if that’s what it would take to heal wounds.
Bangladesh then needs to take a decisive tilt towards Islam.
Muslims in India & Pakistan (not leaders) have a decisively Islamic outlook (despite their splits and differences). Muslims in Bangladesh do not! Their outlook and priorities are based on Bangali Nationalism and Bangla Motherland. This needs to change and it has nothing to do with Pakistan.
Cut Pakistan completely from the picture and move towards Islam. Everything else is secondary.
This cannot be undone and I am sure it will be greatly appreciated.